may, from time to time in one or more offerings, offer and sell up to $50.0 million in the aggregate of common stock, preferred
stock, debt securities, warrants to purchase shares of common stock or preferred stock or debt securities, or any combination
of the foregoing, either individually or as units comprised of one or more of the other securities.
prospectus provides a general description of the securities we may offer. We will provide the specific terms of the securities
offered in one or more supplements to this prospectus. We may also authorize one or more free writing prospectuses to be provided
to you in connection with these offerings. The prospectus supplement and any related free writing prospectus may add, update or
change information contained in this prospectus. Please read carefully this prospectus, the applicable prospectus supplement,
any related free writing prospectus, and the documents incorporated by reference before you invest in any of our securities. This
prospectus may not be used to offer or sell any securities unless accompanied by the applicable prospectus supplement.
common stock is listed on the NYSE American under the symbol “OCX.” On
September 29, 2017, the last reported sale price of our common stock was $7.55 per
share. The aggregate market value of our outstanding shares of common stock held by non-affiliates, based upon this price, was
approximately $51.4 million. During the 12-month period ending on the date of this prospectus, we have not offered any securities
pursuant to General Instruction I.B.6. of Form S-3.
in our securities involves a high degree of risk. See “Risk Factors” on page 4 of this prospectus
and in the documents incorporated by reference into this prospectus, as updated by the applicable prospectus supplement, any
related free writing prospectus and other future filings we make with the Securities and Exchange Commission that are
incorporated by reference into this prospectus, for a discussion of the factors we urge you to consider carefully before
deciding to purchase our securities.
may sell these securities directly to investors, through agents designated from time to time or to or through underwriters or
dealers. For additional information on the methods of sale, please see the section titled “Plan of Distribution”
in this prospectus. If any underwriters are involved in the sale of any securities with respect to which this prospectus is being
delivered, the names of such underwriters and any applicable commissions or discounts will be set forth in a prospectus supplement.
The price to the public of such securities and the net proceeds we expect to receive from such sale will also be set forth in
a prospectus supplement.
the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or
determined if this prospectus or any accompanying prospectus supplement is truthful or complete. Any representation to the contrary
is a criminal offense.
date of this prospectus is October 16, 2017